注射成型立构复合聚乳酸的热变形性能分析

采用左旋聚乳酸（PLLA）和右旋聚乳酸（PDLA）为原料,采用熔融共混法制备了立构复合聚乳酸（SC?PLA）粉末,再通过注射成型制备了SC?PLA样条,并通过差示量热扫描仪（DSC）和热变形温度测定仪对SC?PLA粉末和样条的熔融、结晶情况和热变形性能进行了表征分析。结果表明,SC?PLA粉末的结晶能力与初始熔融状态直接相关;当熔融温度为220~230 ℃时,SC?PLA粉末的熔融稳定时间增加,有助于SC?PLA体系结晶,该温度适合SC?PLA的注射成型加工;SC?PLA样条中SC?PLA结晶度越高,均聚物PLA结晶度越低,越有助于样条热变形性能的提高;低注射温度和以SC?PLA粉末、PLLA、PDLA为原料成型有助于SC?PLA样条在220 ℃下加热再退火后获得较高的SC?PLA结晶度,其热变形温度最高可达到150 ℃以上;注射成型过程中,有利于保留更多SC?PLA晶体和提高SC?PLA结晶度的方式,有助于提高样条在退火后的热变形性能。     

二乙二醇醚马来酸酯钙/锌热稳定剂的制备及应用研究

以马来酸酐和二乙二醇醚为原料在无催化剂条件下制得二乙二醇醚马来酸酯（MD）,此分子结构中具有酯基、醚键及碳碳双键,将此中间产物分别与乙酸钙、乙酸锌反应,制得二乙二醇醚马来酸酯钙/锌盐（MD?Ca/Zn）。通过傅里叶红外测试分析了热稳定剂产物的结构,分子中含有醚键、酯基、碳碳双键、羧酸盐结构,可作为PVC主效热稳定剂。通过刚果红法、热老化法、热失重法、电导率等检测方法,和市售硬脂酸钙/锌进行对比,验证了热稳定效果及性能,分析了热稳定机理,同时探究了与辅助热稳定剂β?二酮（硬脂酰苯甲酰甲烷）的协同作用。结果表明,当MD?Ca/Zn=2∶1（质量比,下同）时,对PVC的热稳定效果最好;初期白度可以达到40 min,静态热稳定时间为35 min;与热稳定剂总质量10 %的β?二酮复配后PVC的热稳定性能还可进一步提升。     

电动叉车用开关磁阻电机新型集成功率变换器

针对电动叉车用开关磁阻电机（SRM）制动过程中的能量回收问题,研究一种可实现多端口能量灵活转换的新型集成式功率变换器。新型集成式功率变换器采用交错并联双向DC/DC变换器作为传统SRM功率变换器的前端电路,可以在电动及发电模式之间灵活切换。采用超级电容与铅酸蓄电池混合储能,回收减速和下放货物的能量,实现再生制动,并用于加速和举升货物。仿真试验表明所设计新型集成式功率变换器能满足电动叉车频繁起停的要求,并可减小输入输出端的电流波纹,提高能量回收效率。     

基于相变蓄热技术的高过载配电变压器研制与应用

本文中作者提出了一种基于相变蓄热技术的高过载变压器,采用石蜡蓄热方式显著提升其抗过载发热能力,并通过试验验证了其实用价值。     

ZG20CrMoV低合金耐热钢主蒸汽弯管研制

介绍了在普通铸造生产条件下一次性成功铸造出火电厂耐热高压蒸汽弯管的工艺措施，避免了因其材质独特、弯度大、管壁厚而易产生缩孔、缩松、裂纹等缺陷。     

形变与热处理对CuCr合金中Cr相形貌及合金性能的影响

研究了CuCr合金在不同形变与热处理制度下，组织中Cr相形貌、合金力学性能及导电性能的变化。结果表明：当变形量达到70％时，合金中的Cr粒子产生严重的变形，且有开裂现象。在随后高温热处理过程中开裂的Cr粒子发生熔断和球化。适当的形变与热处理能改善CuCr合金的力学性能与导电性能，并从微观组织方面对其原因进行了分析。     

HEAT TREATMENT STRENGTHENING EFFECTS OF RARE EARTHS ON Mg—9Al ALLOY

Mg-9Al-xRE magnesium alloys were studied, where, x is 0, 0.4. 0.8. 1.2 and 1.6% (in weight percent, wt%), respectively. Influence of rare earths (RE) on microstructure and strength in both T4 (solute heat treatment) and T6 (solute heat treatment and artificial ageing treatment) were investigated. Strength of specimen was tested at ambient temperature. The micro structure was analyzed by optical microscopy, scanning electron microscopy (SEM) and X-ray diffraction analysis. RE additions improved T4 tensile strength of the treated alloys. Small addition (0.4wt%) of RE greatly improved the strength of ageing treated (T6) Mg-9Al alloy, but further additions caused decreasing.     

Flexible Furnace Concepts for Vacuum Heat Treatment Combined with High-pressure Gas Quenching

IN the past five years the process combination of vacuum hardening, respectively vacuum carburizing with high-pressure gas quenching was successfully introduced to the market, especially in the manufacture of gears. In the meantime furnace concepts for various applications are available to the industry. In the following report three plant varieties are introduced, which differ in process flexibility and throughput. This report also explains criteria for the selection of a furnace in view of the existing application requirements. Besides this a short introduction is given into the vacuum carburizing process and the high-pressure gas quenching technology.     

含共晶碳化物Fe—Cr—Mn合金在高温含硫气氛中的腐蚀研究

对含碳量为０．５０－２．６３％的Ｆｅ－Ｃｒ－Ｍ合金在８００℃下含硫混合气氛中进行腐蚀试验。用Ｘ射线物相分析法分析了腐蚀产物种类及其相对含量，观察测定了元素在腐蚀产物中的分布及试样亚表层共晶碳化物的腐蚀行为。     

车辆热交换器铝合金管的高频焊接

管材所用铝合金带料为三层复合材料,外层为Al-Si钎料层,中间为Al-Mn芯材,内层为Al-Zn防腐层。带材经成型机组成型后经高频焊接而成。研究表明:采用高频焊接铝合金管焊缝成形美观、无气孔等缺陷,焊速高,焊缝微观组织均匀,是一种理想的焊接工艺。